Winter squash is a warm season vegetable that grows and produces well in Arizona. It differs from summer squash in that it is harvested and eaten in the mature fruit stage, when the seeds within have matured fully and the skin has hardened into a tough rind. When ripened to this stage, fruits of most varieties can be stored for use throughout the winter. Pumpkins are also closely related to winter squash. It's too late to plant winter squash this season, but the following information should assist those currently growing it or inspire others to grow it next year.

The ideal time to plant winter squash in the Verde Valley is between May 10 and July 1. Seeds do not germinate well in cold soil and seedlings are damaged by frost, so, the later planting dates are probably best. Most gardeners plant squash on small mounds. I prepare soil for squash mounds by digging a 2 foot wide/1 foot deep hole and placing a couple of shovels of rabbit manure or compost. Plant 5 seeds per mound and thin to 2 or 3 plants per mounds when they are well established. Vining squash plants require considerable growing space and are best suited for large gardens. The bush and semi-vining types can be grown in smaller gardens.

After germination, you should keep your squash patch weeded and regularly irrigated. As soon as the plants occupy the allotted space, weeds will be shaded out. At this point, your work is done and you can let the bees will take over. Each plant has male and female flowers. Bees visit both sexes of flowers and fertilize the female flowers after which, the female flowers produce squash fruits.

Winter squash can be harvested whenever the fruits have turned a deep, solid color and the rind is hard. Harvest the main part of the crop in September or October, before heavy frosts hit your area. Cut squash from the vines carefully, leaving two inches of stem attached if possible. Avoid cuts and bruises when handling. Fruits that are not fully mature, have been injured, have had their stems knocked off, or have been subjected to heavy frost do not keep and should be used as soon as possible or be composted (watch for seedlings in the compost).

After harvest, winter squash should be stored in a dry location where the temperature is between 50 and 55°F. For prolonged storage, do not pile squash more than two fruits deep. It is best to place the squash in a single layer so that they do not touch each other.

Squash bugs attack vines as the fruit begin to set and increase in numbers through the late summer, when they can be quite damaging to maturing fruit. They hatch and travel in groups, which seem to travel in herds until they reach maturity. Using the proper insecticide when the numbers of this pest are still small minimizes damage. Insecticides should only be when damage is serous. If you decide to apply an insecticide, use a product labeled for the specific pest and vegetable crop, follow label directions, and spray it in the early evening to minimize impacts on bees.

Winter squash is a source of complex carbohydrate (natural sugar and starch) and fiber. Winter squash is also a source of potassium, niacin, and iron. Yellow varieties are also high in beta-carotene. Steamed squash also stores well in the freezer. Before I stop, I must confess that I am not a great fan of eating plain old winter squash. However, when steamed and prepared like pumpkin, they make excellent pies, cookies, and nut breads.

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/.